In this presentation an overview of novel antipsychotic ziprasidone was given and the design of all three studies in which Croatian investigators took part was fully decribed. Although typicalphenothiazine and buty- rophenone derivatives continue to be widely prescribed, much more attention has been focused on newer antipsychotic agents. Ziprasidone was developed with the intent of finding a compound that potently blocks D2 receptors, but which binds with even greater affinity to cerebral S-HT^ receptors. Ziprasidone effectively amelio¬rates positive, negative, and depressive symptoms associated with psychosis. Initial evidence suggests an effective dosage range of 80-160 mg/day. Ziprasidone is well tolerated by adult subjects and the most frequently reported treatment-emergent adverse events reported in ziprasidone-treated subjects were insomia, headache and somnolence. However, weight gain - a typical side-effect of antipsychotics - was not observed with this novel drug. Ziprasidone should be discontinued in patients found to have persistent QTcmea- surements >S00msec. Croatian investigators took part in three studies of the novel antipsychotic ziprasidone. The first evaluated ziprasidone ver¬sus risperidone, i.e. the comparative efficacy of ziprasidone versus risperidone in the treatment of acute exacerbation of schizophrenia and schizoaffective disorder. The second study was an open exten¬sion study evaluating the safety and tolerability of oral ziprasidone in the treatment of patients who had successfully completed previous ziprasidone study, and the third study assessed ziprasidone versus olanzapine in the treatment of chronic schizophrenia or schizo¬affective disorder. Although final analyses of ziprasidone studies carried out in Croatia were not yet finished, we could conclude that our clinical experience confirmed the efficacy and safety of ziprasidone.